ID | 54566 |
フルテキストURL | |
著者 |
Morita, Ryohei
Graduate School of Natural Science & Technology, Okayama University
Fukunishi, Mika
Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University
Kubota, Kei
Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University
Komaba, Shinichi
Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University
Nishimura, Naoto
Department of Chemistry and Materials Technology, Kyoto Institute of Technology
Yumura, Takashi
Department of Chemistry and Materials Technology, Kyoto Institute of Technology
Deguchi, Kenzo
National Institute for Materials Science
Ohki, Shinobu
National Institute for Materials Science
Shimizue, Tadashi
National Institute for Materials Science
|
抄録 | We examined the state of sodium electrochemically inserted in HC prepared at 700–2000 °C using solid state Na magic angle spinning (MAS) NMR and multiple quantum (MQ) MAS NMR. The 23Na MAS NMR spectra of Na-inserted HC samples showed signals only in the range between +30 and −60 ppm. Each observed spectrum was ascribed to combinations of Na+ ions from the electrolyte, reversible ionic Na components, irreversible Na components assigned to solid electrolyte interphase (SEI) or non-extractable sodium ions in HC, and decomposed Na compounds such as Na2CO3. No quasi-metallic sodium component was observed to be dissimilar to the case of Li inserted in HC. MQMAS NMR implies that heat treatment of HC higher than 1600 °C decreases defect sites in the carbon structure. To elucidate the difference in cluster formation between Na and Li in HC, the condensation mechanism and stability of Na and Li atoms on a carbon layer were also studied using DFT calculation. Na3 triangle clusters standing perpendicular to the carbon surface were obtained as a stable structure of Na, whereas Li2 linear and Li4 square clusters, all with Li atoms being attached directly to the surface, were estimated by optimization. Models of Na and Li storage in HC, based on the calculated cluster structures were proposed, which elucidate why the adequate heat treatment temperature of HC for high-capacity sodium storage is higher than the temperature for lithium storage.
|
備考 | This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. https://creativecommons.org/licenses/by-nc/3.0/
|
発行日 | 2016-07-25
|
出版物タイトル |
Journal of Materials Chemistry A
|
巻 | 4巻
|
号 | 34号
|
出版者 | ROYAL SOC CHEMISTRY
|
開始ページ | 13183
|
終了ページ | 13193
|
ISSN | 2050-7488
|
NCID | AA12603290
|
資料タイプ |
学術雑誌論文
|
言語 |
英語
|
著作権者 | © Authors
|
論文のバージョン | publisher
|
DOI | |
Web of Science KeyUT |